There are several ways to deal with this......
1) get professional help. there are certain products that make your penis less sensitive. Keep in mind that the source of your problem might be your brain and not your tool....
2) Have more sex, porn and everything else... There wll be less tension and excitement when it comes to the real deal..
3) Maybe not a very good idea....but 'blue pills' have some side effects. Besides of the boner, it may giv you a little headache, blush and.......delay the eruption...
Google a little bit please....